Process of manufacturing manganese and alloys of manganese free from carbon



STATES PATENT VILLIAM H. GREENE AND VVILLIALWI H. l/VAHL, OFPHILADELPHIA, PENNSYLVANIA.

PROCESS OF MANUFACTURlNG MANGANESE AND ALLOYS 0F MANGANESE FREE FROMCARBON.

SPECIFICATION forming part of Letters Patent No. 489,303, dated January3, 1893.

Application filed July 2, 1892. $erial No. 488,739. (No specimens.)

To all whom it may concern.-

Be it known that we, VILLIAM H. GREENE and WILLIAM H. WAHL, bothcitizens of the United States, and residents of Philadelphia,Pennsylvania, have invented a Process of Manufacturing Manganese andAlloys of Manganese Free from Carbon, of which the fol lowing is aspecification.

The object of our invention is to manufacture on a commercial scale,manganese and manganese alloys which will be wholly free from carbon.

The industrial application of manganese in the operations of steelmaking, and recently in the manufacture of the alloys known as manganesesteel, manganese bronze, and other metallic mixtures in which this metaleuters as an essential constituent, has made it desirable to producemetallic manganese on a commercial scale in a state of the highestpossible purity, and cheaply enough to permit of its use in theseoperations. Hitherto, manufacturers, for the want of the pure metal,have been compelled to employ the alloys of manganese and iron made inthe blast furnace and known as spiegeleisen and ferro-manganese, thesealloys containing from six to eighty-five per cent. of manganese withfiveor six percent. of carbon, and small quantities of silicon,phosphorus and other impurities. The most persistent efforts heretoforemade to produce, cheaply enough for industrial purposes, a manganesepractically free from carbon and iron have failed.

The processes heretofore employed or proposed for the production ofmanganese may produced by numerous modifications of this general planinvariably contained about six per cent. of combined carbon, even whenthe quantity of carbon employed was insufficient to effect a completereduction of the oxides,

nor could this carbon be eliminated from the metal by fusing it, inpresence of sundry fluxes, with more oxides. These results 0011- firmthose of other experimenters. In another group, may be placed thoseprocesses in which the chloride or fluoride of manganese is reduced bysubjecting it, under various circumstances, to the action of sodium. Bymethods of this class manganese may be obtained chemically pure but theyhave proved far too costly to be used commercially. The electrolyticmethod of reduction has been experimentally attempted on a small scale,but the impossibility of using a carbonaceous anode in this operationbecause of the certainty of forming a carbonide of the metal is one ofthe several difficulties which the electro-metallurgist has not beenable to overcome. Alloys of copper containing varying proportions ofmanganese have indeed been made successfully on a commercial scale bythe electric furnace method, but the necessity of using electrodes ofcarbon in this method renders the production of the pure metalimpossible.

WVe will now proceed to describe our invention of a process forproducing metallic manganese entirely free from carbon, and containingonly such slight quantities of iron and other impurities, such assilicon, phosphorus, &c., as are within the permissible limit in themanufacture of metals on a large scale, where the term commercially pureis used to designate the product.

In the operation of our process, the manganese ore composedsubstantially of manganese di-oxide, and contaminated with more or lessiron, is finely ground and digested with sulphuric acid, (specificgravity 1.8a) diluted with two or three times its volume of water. Theiron passes into solution, while the oxides of manganese are onlyslightly affected. We have found that the above named proportions ofdilution for the acid should be adhered to in order to obtain the mostsatisfactory results, since, if a more concentrated acid solution beused, the manganese oxide will be powerfully attacked and dissolved,while, if a more dilute acid be employed, the time consumed in theremoval of the iron will be unduly prolonged. The operation isfacilitated by constant agitation of the mixture so as to expose freshportions of the ore to the action of the acid. When the removal of theiron is accomplished, the liquor is drawn off and the purified ore iswashed with water to remove all traces of the acid, and dried. If theoperation has been conducted properly, the percentage of iron in the oreis thereby reduced to a few tenths of one per cent. The acid liquid maybe treated by well known methods for the recovery of the waste in theform of copperas. In operating with a commercially pure ore, or wherethe presence of iron in the metal is not objectionable, this preliminarypurification, will, of course, not be necessary. The ore is now to bereduced to the condition of a lower oxide, preferably to that ofmanganese monoxide, by any convenient method. The reduction to manganesemonoxide presents several important practical ad vantages. Manganesemonoxide, being the lowest known oxide of manganese, will demand less ofthe reducing substance to subsequently remove its oxygen, and this oxideis better adapted for such subsequent reduction by reason of beingfusible at a much lower temperature than the other oxides of the metal.

For the reduction of the manganese di-oxide to a lower oxide, we havefound the following method to answer satisfactorily. The commerciallypure native ore, or the commercially purified ore is introduced into anoven having preferably the form of a horizontal cylinder, and mounted soas to permit of being rotated abouta horizontal axis. The oven isprovided with suitable openings for the admission and exit of gases. Inan oven answering to this general description,the ore is heated toredness in a current of reducing gas, for which purpose we may employpetroleum-vapor, hydro-carbon gases, carbon monoxide, or water gas. Bythis operation, di-oxide and sesqui-oxide (corresponding respectively tothe chemical formulae M110 Mn 0 are converted first to theprotosesquioxide (M11 0 and then to the gray oxide or monoxide of thecomposition MnO.

The final step of our process consists in reducing the manganeseprotosesquioxide or,

manganese monoxide to the metallic state. lVe accomplish this by heatingit in contact with a metal capable of removing and appropriating itsoxygen and setting free the manganese. The presence of a fluxfacilitates the re-action and the gathering into a single mass of theresulting metal, which, when no flux is used in the operation, is founddisseminated through the mixture in the form of globules or shot, whichrequire to be separated, collected, and remelted. In this operation weuse acrucible or chamber formed of, or lined with, a material free fromcarbon, and preferably also free from silica.

For certain uses for which the metal may be found suitable, the presenceof silicon in small quantity, say to the amount of three per cent, isnot detrimental, and for metal of this quality, the reduction of themanganese protosesquioxide or monoxide may be performed in siliciouscrucibles.

We have found the following mode of operation to yield the best results.Manganese monoxide is introduced into a crucible or chamber lined withlime or magnesia or other material free from carbon and silica andcapable of resisting the action of the flux, metallic aluminum is addedin the proportion required to effect the reduction of the manganesemonoxide present, (that is to say in the proportion of fifty-five partsof aluminum to two hundred and thirteen parts of manganese monoxide) andthere is also added a quantity of some suitable flux. This may consisteither of fluorides such as fiuor-spar or cryolite or mixtures of both,or, in case the operation be conducted in silicious vessels of silicatesof potassium, sodium, calcium, aluminium, and magnesium in variousproportions. The mixture is then heated to the temperature at which thereaction takes place. If desired, however, the manganese monoxideintimately incorporated with a convenient quantity of the flux, may beintro duced into the reducing chamber or crucible, together with thealuminum in the proportions above named, and the mixture then heated tothe temperature at which the reaction takes place. If instead ofmonoxide, the protosesquioxide is under treatment the pro.- portion ofoxygen-appropriati n g metal should be correspondingly increased, inaccordance with the change in chemical equivalents involved. \Vhen thepresence in the metal, of silicon in small proportion is notobjectionable, the reduction may easily and effectively be accomplishedby either of the foregoing procedures, by the use of a readily fusiblesilicious flux, such for example as powdered glass, and the reductionmay be effected insilicious crucibles.

To avoid the contamination of the resulting metal with aluminum, we havefound it preferable to add in the reducing operation, somewhat lessaluminum than would be required to reduce the manganese oxidecompletely. By careful observance of this precaution the quantity ofaluminum remaining in the product will be inappreciable.

By the several operations above described, there results metallicmanganese entirely free from carbon and containing only such smallquantities of iron, silicon, and other impurities, that, for commercialpurposes, it may be considered to be pure. A product of such high gradeof purity has not yet, to our knowledge, been made on a commercialscale, and we are enabled by our process to manufacture it at alowercost than has heretofore been possible. The resulting metalexhibits the property of being quite stable in the air, an evidence ofits freedom from carbon, while all the so-called manganese reduced incontact with carbon, after exposure to the air for a few days only,disintegrates and falls to powder. The residuum containing the aluminumoxide may be treated if found desirable, to regenerate thd'aluminum.

If, instead of pure manganese, an alloy of manganese is desired, themetal which it is wished to alloy with the manganese may be introducedeither'with the aluminum, which is used as the reducing agent, or withthe ore, as in the herein described case where a ferruginous manganeseore is employed in the manufacture of a ferromanganese entirely freefrom'carbon.

Having now described our process, we claim as our invention and desireto secure by Letters Patent-:-

1. In the art of producing metallic manganese, or manganese alloys freefrom carbon, the herein described process which consists in reducing theore to the condition of a lower oxide, and then reducing such loweroxide to the metallic state by heating it, in a reducing chamber freefrom carbon, in contact with substantially the chemically equivalentquantity of a metal capable of removing its oxygen, substantially asdescribed.

2. In the art of producing metallic manganese, or manganese alloys freefrom carbon, the herein described process which consists in reducing theore to the condition of a lower oxide, and then reducing said loweroxide to the metallic state byheating it, ina reducing chamber free fromcarbon and silica, in contact with substantially the chemical equivalentquantity of a metal capable of reducing its oxygen, substantially asdescribed.

3. In the art of producing metallic manganese, or manganese alloys freefrom carbon, the herein described process which consistsin digesting themanganese ore with diluted sulphuric acid, then reducing the purifiedore to the condition of a lower oxide, and then reducing such loweroxide to the metallic state by heating, in a reducing chamber free fromcarbon, in contact with substantially the chemically equivalent quantityof a metal capable of removing its oxygen, substantially as described.

4. In the art of producing metallic manganese, or manganese alloys freefrom carbon, the herein described process which consists in digestingthe manganese ore with diluted sulphuric acid, then reducing thepurified ore to the condition of a lower oxide and then reducing suchlower oxide to the metallic state by heating it, in a reducing chamberfree from carbon and silica, in contact with substantially thechemically equivalent quantity of a metal capable of removing itsoxygen, substantially as described.

5. In the art of producing metallic manganese or manganese alloys freefrom carbon, the herein described process which consists in reducing theore to manganese monoxide, then reducing said monoxide to the metallicstate by heating it in contact with substantially the chemicallyequivalent quantity of a metal capable of removing its oxygen,substantially as set forth.

In testimony whereof we have signed our names to this specification inthe presence of two subscribing witnesses.

IVILLIAM H. GREENE. WILLIAM H. WAHL. Witnesses:

HENRY HOWSON, HARRY S ITH.

